TECHNICAL FIELD
[0001] The present invention relates to a molten metal plating facility and a molten metal
plating method for plating a strip with molten metal.
BACKGROUND ART
[0002] FIG. 10 is a schematic diagram for describing a typical molten metal plating facility.
FIG. 11 is a cross sectional view taken along line G-G' in FIG. 10, as seen in the
direction of the arrow. As shown in FIG. 10, a typical molten metal plating facility
basically includes a sink roll 11 and a pair of wiping nozzles 12a, 12b. The sink
roll 11 is disposed in a molten metal bath Mm containing zinc, for instance, and is
configured to guide a strip S that travels continuously. Furthermore, the pair of
wiping nozzles 12a, 12b are disposed so as to face the front surface side and the
back surface side of the strip S guided upward from the molten metal bath Mm. Further,
the pair of wiping nozzles 12a, 12b are configured to discharge air streams Ea, Eb
of gas jet to remove excess molten metal adhering to the strip S.
[0003] Accordingly, the strip S is guided into the molten metal bath Mm by the sink roll
11, immersed in the molten metal bath Mm to be plated with molten metal, and is guided
outside the molten metal bath Mm (upward). Then, toward each of the front surface
and the back surface of the strip S outside the molten metal bath Mm, the wiping nozzles
12a, 12b discharge air streams Ea, Eb, respectively. The air streams Ea, Eb discharged
as described above remove the excess molten metal adhering to the strip S, and thereby
the plating thickness of the strip S is adjusted.
Citation List
Patent Literature
SUMMARY
Problems to be Solved
[0005] In the above described typical molten metal plating facility, as shown in FIG. 10,
in a side view, the wiping nozzles 12a, 12b facing each other discharge the air streams
Ea, Eb toward the front surface and the back surface of the strip S in a perpendicular
direction or a substantially perpendicular direction. Furthermore, as shown in FIG.
11, in a top view, the air streams Ea, Eb are discharged over a width that is greater
than the width of the strip S.
[0006] The discharged air streams Ea, Eb hit the front surface and the back surface of the
strip S in a perpendicular direction or a substantially perpendicular direction, and
thus the flow after hitting becomes unstable. In particular, at an end portion of
the strip S, a flow that escapes outward in the strip width direction is generated,
as shown in the dotted-line region of FIG. 11. Thus, the peak pressure changes at
the end portion of the strip S. When the pressure is low, the wiping performance deteriorates,
and the thickness of the molten metal coating Mc (plating) at the end portion increases.
That is, at the end portion of the strip S, the thickness of the molten metal coating
Mc adhering thereto becomes thicker than in the vicinity of the center section of
the strip S with respect to the strip width direction, which is called "edge over-coating".
The molten metal coating Mc with an increased thickness overflows and scatters from
the edge of the strip S, which produces splashes Ms.
[0007] Furthermore, the discharged air streams Ea, Eb hit each other at the outer side of
the end portion of the strip S, which generates a turbulent flow. Such a turbulent
flow generated as described above spreads out the splashes M scattering from the edge
of the strip S, and the splashes M adhere to the vicinity of outlets of the wiping
nozzles 12a, 12b. As the adhering splashes Ms accumulate and develop, the splashes
Ms disturb the flow of air streams Ea, Eb from the wiping nozzles 12a, 12b, which
may result in uneven wiping. As a result, the surface quality of the strip S may deteriorate
(formation of pattern or defect on the plated surface).
[0008] Next, Patent Documents 1 to 4 will be described briefly. Patent Document 1 discloses,
in order to solve the above problem, providing a baffle plate on the outer side of
the end portion of the strip to reduce splashes. However, if the distance between
the strip and the baffle plate is reduced, slight meandering of the strip during travel
may cause the strip and the baffle plate to make contact with each other, and the
quality of the end portion of the strip may deteriorate. On the other hand, if the
distance between the strip and the baffle plate is increased, contact could be avoided,
but the baffle plate cannot exert the effect to prevent adhesion of splashes.
[0009] Furthermore, Patent Documents 2 to 4 disclose providing an auxiliary nozzle separately
from the wiping nozzles. However, the auxiliary nozzles disclosed in Patent Documents
2 to 4 discharge an air stream which mainly hits the end surface of the strip in order
to enhance the wiping effect, and thus do not have the effect to prevent adhesion
of splashes.
[0010] The present invention was made in view of the above issue, and an object is to provide
a molten metal plating facility and a molten metal plating method whereby it is possible
to prevent adhesion of splashes to prevent deterioration of the surface quality of
the strip.
Solution to the Problems
[0011] A molten metal plating facility for plating a strip with molten metal by guiding
the strip into a molten metal bath and then guiding the strip upward, according to
the present invention for solving the above problem, includes: a pair of wiping nozzles
disposed so as to face a front surface side and a back surface side of the strip guided
upward and being configured to discharge first air streams toward a first collision
point inside the strip such that the first air streams spread out in a strip width
direction of the strip; and a pair of outer nozzles disposed so as to face a front
surface side and a back surface side of an extended plane on an outer side of the
strip with respect to the strip width direction, above the wiping nozzles and on each
of both outer sides of the strip with respect to the strip width direction, the outer
nozzles being configured to discharge second air streams toward a second collision
point within the extended plane and below the first collision point.
[0012] A method of plating a strip with molten metal by guiding the strip into a molten
metal bath and then guiding the strip upward, according to the present invention for
solving the above problem, includes: by using a pair of wiping nozzles disposed so
as to face a front surface side and a back surface side of the strip guided upward,
discharging first air streams toward a first collision point inside the strip, such
that the first air streams spread out in a strip width direction of the strip; and
by using a pair of outer nozzles disposed so as to face a front surface side and a
back surface side of an extended plane on an outer side of the strip with respect
to the strip width direction, above the wiping nozzles and on each of both outer sides
of the strip with respect to the strip width direction, discharging second air streams
toward a second collision point within the extended plane and below the first collision
point.
Advantageous Effects
[0013] According to the present invention, it is possible to prevent adhesion of splashes
and prevent deterioration of the surface quality of the strip.
[0014] The baffle plate shown in Patent Document 1 may make contact with an end portion
of a strip as an object. In the present invention, the second air streams discharged
from the outer nozzles are used, and thus there is no risk of contact with an end
portion of a strip as an object. Furthermore, the auxiliary nozzle shown in Patent
Documents 2 to 4 is not disposed on the outer side of the end portion of the strip
with respect to the plate width direction, and does not form an air stream on the
outer side of the end portion of the strip with respect to the plate width direction.
Thus, the auxiliary nozzle cannot prevent adhesion of splashes, in contrast to the
present invention.
BRIEF DESCRIPTION OF DRAWINGS
[0015]
FIG. 1 is a schematic diagram for describing an example (working example 1) of an
embodiment of the molten metal plating facility according to the present invention.
FIG. 2 is a cross-sectional view taken along line C-C' in FIG. 1 in the direction
of the arrow.
FIG. 3 is a cross-sectional view taken along line D-D' in FIG. 1 in the direction
of the arrow.
FIG. 4 is a diagram for describing an arrangement relationship of a strip, wiping
nozzles, and outer nozzles with respect to the strip thickness direction, in the molten
metal plating facility shown in FIG. 1.
FIG. 5 is a diagram for describing an arrangement relationship of a strip, wiping
nozzles, and outer nozzles with respect to the strip width direction, in the molten
metal plating facility shown in FIG. 1.
FIG. 6 is a schematic diagram for describing another example (working example 2) of
the embodiment of the molten metal plating facility according to the present invention.
FIG. 7 is a schematic diagram for describing the configuration of a control system,
in the molten metal plating facility shown in FIG. 6.
FIG. 8 is a schematic diagram for describing another example (working example 3) of
the embodiment of the molten metal plating facility according to the present invention.
FIG. 9 is a schematic diagram for describing another example (working example 4) of
the embodiment of the molten metal plating facility according to the present invention,
describing the configuration of the control system.
FIG. 10 is a schematic diagram for describing a typical molten metal plating facility.
FIG. 11 is a cross-sectional view taken along line G-G' in FIG. 10 in the direction
of the arrow.
DETAILED DESCRIPTION
[0016] Embodiments of the molten metal plating facility according to the present invention
will now be described in detail with reference to FIGs. 1 to 9. The molten metal plating
method according to the present invention is to be performed in the molten metal plating
facility of each example, as described below.
(Working example 1)
[0017] The molten metal plating facility of the present working example is based on a typical
molten metal plating facility shown in FIG.s 10 and 11. That is, as shown in FIG.
1, the molten metal plating facility basically includes a sink roll 11 and a pair
of wiping nozzles 12a, 12b. Similarly to the typical configuration, the sink roll
11 is disposed inside a molten metal bath Mm containing zinc, for instance, and is
configured to guide a strip S that travels continuously. Furthermore, similarly to
the typical configuration, the pair of wiping nozzles 12a, 12b are disposed to face
the front surface side and the back surface side of the strip S guided upward from
the molten metal bath Mm. Further, the pair of wiping nozzles 12a, 12b are configured
to discharge air streams Ea, Eb of gas jet to remove excess molten metal adhering
to the strip S. Herein, the same features as those in a typical molten metal plating
facility shown in FIGs. 10 and 11 are associated with the same reference numerals.
[0018] As shown in FIG. 1, in a side view, the wiping nozzles 12a, 12b facing each other
are configured to discharge the air streams Ea, Eb (first air streams) toward the
front surface and the back surface of the strip S in a perpendicular direction or
a substantially perpendicular direction, toward the collision point A (first collision
point) inside the strip. Furthermore, as shown in FIG. 3, in a top view, the wiping
nozzles 12a, 12b have outlets 13a, 13b elongated in the strip width direction, so
as to discharge the air streams Ea, Eb over a width that is greater than the strip
width of the strip S. While the outlets 13a, 13b normally have the same width as the
strip width of the strip S, the width may be slightly greater or smaller.
[0019] As shown in FIGs. 2 and 3, the outlets 13a, 13b may include masks 14a, 14b that cover
the outlets 13a, 13b. The width of the outlets 13a, 13b, with respect to the strip
width direction, can be changed by moving the masks 14a, 14b in the strip width direction
in accordance with the strip width of the strip S. Thus, even if the width of the
strip S changes, the air streams Ea, Eb are discharged in accordance with the strip
width of the strip S, or slightly longer or shorter than the same. The masks 14a,
14b may be configured such that the positions of the masks 14a, 14b are adjustable
depending on the strip width of the strip S, on the basis of the strip end position
of the end portion of the strip S detected by a strip end detection sensor 21 described
below.
[0020] In addition to the above described configuration, the molten metal plating facility
of the present working example includes two pairs of outer nozzles 15a, 15b. The two
pairs of outer nozzles 15a, 15b are disposed above the wiping nozzles 12a, 12b, on
both outer sides of the strip S with respect to the strip width direction. Further,
the two pairs of outer nozzles 15a, 15b are disposed so as to face the front surface
side and the back surface side of a virtual extended plane (not shown) on the outer
side of the strip S with respect to the strip width direction, respectively. In other
words, the pair of outer nozzles 15a, 15b are disposed plane-symmetrically with reference
to the extended plane.
[0021] As shown in FIG. 1, the outer nozzles 15a, 15b have outlets 16a, 16b, which discharge
gas jet air streams Fa, Fb (second air streams) from above the outlets 13a, 13b of
the wiping nozzles 12a, 12b. The air streams Fa, Fb are discharged toward the collision
point B (second collision point) disposed within the extended plane and below the
collision point A. That is, the positions and inclinations of the outer nozzles 15a,
15b (outlets 16a, 16b) are set so as to discharge the air streams Fa, Fb toward the
collision point B below the collision point A of the air streams Ea, Eb, from above
the air streams Ea, Eb.
[0022] Further, as shown in FIGs. 2 and 3, the outer nozzles 15a, 15b (outlets 16a, 16b)
are configured to form air streams Fa, Fb having a predetermined width in the strip
width direction, on the outer side of an end portion of the strip S with respect to
the strip width direction. For instance, the outlets 16a, 16b may have a linear shape
elongated in the strip width direction. Further, the outer nozzles 15a, 15b (outlets
16a, 16b) are configured such that the air streams Fa, Fb having a predetermined width
are parallel to each other along the strip width direction as seen from above (see
FIG. 3). For instance, the outlets 16a, 16b having a linear shape may be disposed
parallel to each other along the strip width direction.
[0023] Also in the molten metal plating facility of the present working example having the
above described configuration, the strip S is guided into the molten metal bath Mm
by the sink roll 11, immersed in the molten metal bath Mm, and is guided outside the
molten metal bath Mm (upward). Accordingly, a molten metal coating Mc is formed on
the strip S, and plating is applied. Then, toward each of the front surface and the
back surface of the strip S outside the molten metal bath Mm, the wiping nozzles 12a,
12b discharge air streams Ea, Eb, respectively. The air streams Ea, Eb discharged
as described above remove the excess molten metal from the strip S, and thereby the
plating thickness of the molten metal coating Mc (plating) adhering to the strip S
is adjusted.
[0024] Also in the typical molten metal plating facility of the present working example,
the wiping nozzles 12a, 12b facing each other discharge the air streams Ea, Eb toward
the front surface and the back surface of the strip S in a perpendicular direction
or a substantially perpendicular direction in a side view, as shown in FIG. 1. Furthermore,
as shown in FIG. 3, in a top view, the air streams Ea, Eb are discharged over a width
that is greater than the strip width of the strip S.
[0025] Thus, also in the molten metal plating facility of the present working example, the
discharged air streams Ea, Eb hit the front surface and the back surface of the strip
S in a perpendicular direction or a substantially perpendicular direction, and thus
the flow after hitting becomes unstable. In particular, at an end portion of the strip
S, a flow that escapes outward in the strip width direction is generated, as shown
in the dotted-line region of FIG. 3. Furthermore, the discharged air streams Ea, Eb
hit each other at the outer side of the end portion of the strip S, and generate a
turbulent flow. Thus, similarly to the typical molten metal plating facility, edge
over-coating occurs, and splashes Ms scatter from the edge of the strip S.
[0026] However, in the molten metal plating facility of the present working example, outer
nozzles 15a, 15b are provided separately from the wiping nozzles 12a, 12b. The air
streams Fa, Fb from the outer nozzles 15a, 15b form two gas curtains of the air streams
Fa, Fb, on the outer side of each end portion of the strip S with respect to the strip
width direction. The two gas curtains of the air streams Fa, F form a space like a
V-shaped groove whose bottom is the collision point B.
[0027] Then, before spreading out, the splashes Ms scattering from the edge of the strip
S (in particular, edge at the collision point A) are trapped inside the space (like
a V-shaped groove) between the gas curtains formed by the air streams Fa and Fb. Then,
the splashes Ms are incorporated into the air streams Fa and Fb to be entrained, and
thereby blown off downward. Accordingly, unlimited diffusion of the splashes M scattering
from the edge of the strip S is prevented, and adhesion of the splashes M to the outlets
13a, 13b of the wiping nozzles 12a, 12b is prevented.
[0028] In the above configuration, the splashes Ms may pass between the two air streams
Fa, Fb without being entrained by the air streams Fa, Fb. To reduce such risk, it
is desirable to situate the collision point B of the two air streams Fa, Fb at where
the splashes Ms from the strip S are produced, that is, below and in the vicinity
of the collision point A.
[0029] Further, the air stream Fa and the air stream Fb having a predetermined width may
not necessarily be parallel along the strip width direction, and the outer nozzles
15a, 15b (outlets 16a, 16b) may be configured such that the distance between the air
streams Fa, Fb decreases (narrows) toward the outer side in the strip width direction.
In this case, it is desirable to change the angle of the outlets 16a, 16b closer to
the vertical direction toward the outer side in the strip width direction, so as to
ensure that the collision point B is always below the collision point A. Further,
in this case, the shape of the outlets 16a, 16b is not limited to a linear shape,
and may be a staircase shape or curved shape.
[0030] Furthermore, in the above configuration, it is desirable that the pressures (discharge
pressures) of the air streams Fa, Fb at the outer nozzles 15a, 15b are higher than
the pressures (discharge pressures) of the air streams Ea, Eb at the wiping nozzles
12a, 12b. For instance, in the above configuration, the pressure of gas supplied to
the wiping nozzles 12a, 12b and the pressure of gas supplied to the outer nozzles
15a, 15b can be set individually. Further, the pressure of the gas supplied to the
outer nozzles 15a, 15b may be set to be higher than the pressure of the gas supplied
to the wiping nozzles 12a, 12b. On the outer side of the end portion of the strip
S with respect to the strip width direction, the air streams Fa, Fb interfere with
a part of the air streams Ea, Eb. However, the air streams Fa, Fb having greater pressures
than the air streams Ea, Eb dominate, and thus it is easier to prevent diffusion of
the splashes Ms.
[0031] Further, if the pressures of supplied gas cannot be set individually, instead of
the pressures, the opening interval in a direction perpendicular to the strip width
direction may be different between the outlets 13a, 13b of the wiping nozzles 12a,
12b and the outlets 16a, 16b of the outer nozzles 15a, 15b. In this case, the opening
interval between the outlets 16a, 16b is set to be greater than the opening interval
between the outlets 13a, 13b, so as to increase the flow rate per unit length in the
strip width direction. Accordingly, the air streams Fa, Fb having a greater flow rate
per unit length than the air streams Ea, Eb dominate, and thus it is easier to prevent
diffusion of the splashes Ms.
[0032] Next, the positional relationship of the outer nozzles 15a, 15b (outlets 16a, 16b)
relative to the strip S and the wiping nozzles 12a, 12b (outlets 13a, 13b) will be
described with reference to FIGs. 4 and 5. Herein, the strip S is assumed to be traveling
through the center position between the wiping nozzles 12a and 12b.
[0033] Herein, in FIG. 4, the inclination θ is the inclination of the outlets 16a, 16b of
the outer nozzles 15a, 15b with respect to the horizontal direction, i.e., the inclination
of the air streams Fa, Fb with respect to the horizontal direction. Furthermore, the
distance H is the distance in the strip thickness direction from the tips of the outlets
13a, 13b of the wiping nozzles 12a, 12b to the surface of the strip S. Furthermore,
the distance H1 is the distance in the strip thickness direction from the tips of
the outlets 16a, 16b of the outer nozzles 15a, 15b to the surface of the strip S.
Furthermore, the distance b1 is the distance in the height direction from the tips
of the outlets 16a, 16b of the outer nozzles 15a, 15b to the collision point A. Furthermore,
the distance b2 is the distance in the height direction from the collision point A
to the collision point B.
[0034] Furthermore, in FIG. 5, the distance δ is the distance in the strip width direction
from the end portion of the strip S to the end portions of the outlets 13a, 13b of
the wiping nozzles 12a, 12b. Furthermore, the distance δ1 is the distance of the gap
in the strip width direction between the end portion of the strip S and the outer
nozzles 15a, 15b (outlets 16a, 16b). Furthermore, the width w1 is the width in the
strip width direction of the outer nozzles 15a, 15b (outlets 16a, 16b).
[0035] Further, for the outer nozzles 15a, 15b (outlets 16a, 16b), the following positions
(distance H1, b1, δ1) and the inclination θ are adjusted. For instance, a mechanism
is provided to adjust the positions of the collision point A (first collision point)
and the collision point B (second collision point) described above. It is useful to
adjust the positions to enable operation under optimum conditions.
- (1) Adjust the distances H1, b1, and the inclination θ, so that the collision point
B of the air streams Fa, Fb from the outer nozzles 15a, 15b (outlets 16a, 16b) is
at the strip-thickness center of the strip S in the strip thickness direction.
- (2) Adjust the distances H1, b1, and the inclination θ, so that the collision point
B of the air streams Fa, Fb from the outer nozzles 15a, 15b (outlets 16a, 16b) is
lower than the collision point A of the air streams Ea, Eb from the wiping nozzles
12a, 12b in the height direction.
- (3) Situate the outer nozzles 15a, 15b on the outer side, with respect to the strip
width direction, so as to have an interval of the distance δ1 from the end portion
of the strip S in the strip width direction.
[0036] By adjusting the above distance H1, b1, δ1, and the inclination θ, the collision
point B of the air streams Fa, Fb is positioned to be lower than the collision point
A at which the splashes Ms are produced. The space like a V-shaped groove formed by
two curtains of the air streams Fa, Fb has a bottom at the collision point B below
the collision point A, and the extended line of the collision point A in the strip
width direction is positioned inside the space like a V-shaped groove.
[0037] Further, as the outer nozzles 15a, 15b are disposed closer to the end portion of
the strip S, that is, as the distance δ1 decreases, the splashes Ms can be more easily
trapped and incorporated. However, if the outer nozzles 15a, 15b are too close to
the end portion of the strip S, the outer nozzles 15a, 15b may interfere with the
air streams Ea, Eb from the wiping nozzles 12a, 12b and reduce the wiping performance
at the end portion of the strip S. Thus, it is desirable to adjust the distances δ1,
δ taking into account of this point.
[0038] Although not shown in the drawings, the outer nozzles 15a, 15b (outlets 16a, 16b)
are configured such that the positions and the inclinations are adjustable independently
from the wiping nozzles 12a, 12b. Thus, for instance, even in a case where the position
and the inclinations of the wiping nozzles 12a, 12b are changed, it is possible to
adjust the positions and the inclinations of the outer nozzles 15a, 15b (outlets 16a,
16b) so as to satisfy the above conditions (1) to (3).
(Working example 2)
[0039] The molten metal plating facility of the present working example is based on the
molten metal plating facility shown in the above working example 1. Thus, the same
features as those in the molten metal plating facility of working example 1 shown
in FIGs. 1 to 5 are associated with the same reference numerals, and the overlapping
configuration is not described again.
[0040] The position of each end portion of the strip S shifts due to meandering and a change
in the strip width during traveling. In particular, if the traveling speed of the
strip S is high, the changing speed of the position of the end portion of the strip
S increases, and the positions of the air streams Ea, Eb and the positions of the
air streams Fa, Fb may be offset from the initially-set positions in the strip width
direction. As a result, the air streams Fa, Fb from the outer nozzles 15a, 15b may
fail to prevent diffusion of the splashes Ms appropriately.
[0041] To address the above described problem, as shown in FIGs. 6 and 7, the molten metal
plating facility of the present working example further includes a control device
20 (control unit), a strip end detection sensor 21 (strip end detection unit), and
driving devices 22a, 22b (position changing units). While only one end portion of
the strip S is shown in FIG. 7, the other end portion has the same configuration.
[0042] The strip end detection sensor 21 is, for instance, a camera or a photo sensor or
a 2D laser sensor, which detects the strip end position of the end portion of the
strip S with respect to the strip width direction, on the basis of image or detection
signals. Furthermore, the driving devices 22a, 22b are each an electric actuator including
a ball screw, a linear guide, and a servo motor, for instance, for moving the outer
nozzles 15a, 15b in the strip width direction.
[0043] In this configuration, the strip end detection sensors 21 disposed on both end portions
constantly detect the strip end positions of both end portions of the strip S. The
control devices 20 move the outer nozzles 15a, 15b to the positions corresponding
to the strip end positions, with respect to the strip with direction, on the basis
of the detected strip end positions of both end portions of the strip S, by using
the driving devices 22a, 22b provided for each of the end portions.
[0044] Similarly, the positions of the outer nozzles 15a, 15b of each of both end portions
with respect to the strip width direction are adjustable in accordance with the strip
width of the strip S, and the outer nozzles 15a, 15b are adjusted to the positions
for forming the air streams Fa, Fb on the outer side of each end portion of the strip
S in the strip width direction.
[0045] With the above configuration, even if the strip S meanders, the strip end positions
of both end portions of the strip S are constantly detected by the strip end detection
sensors 21, and thus it is possible to adjust the outer nozzles 15a, 15b to appropriate
positions corresponding to the strip end positions. That is, it is possible to maintain
the positions of the outer nozzles 15a, 15b relative to both end portions of the strip
S in the strip width direction at constant positions.
[0046] Accordingly, it is possible to adjust and maintain an appropriate positional relationship
between the splashes Ms produced at each end portion of the strip S and the two air
streams Fa, Fb discharged from the outer nozzles 15a, 15b, in the strip width direction.
For instance, the positional relationship as described in FIG. 5 may be achieved.
As a result, it is possible to appropriately suppress diffusion of the splashes Ms
with the air streams Fa, Fb. Furthermore, it is possible to readily adjust to strips
S having different widths.
(Working example 3)
[0047] The molten metal plating facility of the present working example is also based on
the molten metal plating facility shown in the above working example 1. Thus, the
same features as those in the molten metal plating facility of working example 1 shown
in FIGs. 1 to 5 are associated with the same reference numerals, and the overlapping
configuration is not described again.
[0048] The strip S may be warped, or the strip S may vibrate when traveling. When the strip
S is warped or vibrating, the positions of the air streams Ea, Eb and the positions
of the air streams Fa, Fb may be offset from the initially-set positions in the strip
thickness direction. As a result, the air streams Fa, Fb from the outer nozzles 15a,
15b may fail to prevent diffusion of the splashes Ms appropriately.
[0049] To address the above described problem, as shown in FIG. 8, the molten metal plating
facility of the present working example further includes a plurality of pairs of vibration
control devices 30a and 30b. Each pair is disposed so that the vibration control devices
30a and 30b face the front surface side and the back surface side of the strip S coming
out from the molten metal bath Mm, and a plurality of such pairs of vibration control
devices 30a, 30b are arranged in the strip width direction. The outer nozzles 15a,
15b are mounted to the vibration control devices 30a, 30b of both end portions. The
wiping nozzles 12a, 12b are also attached to the vibration control devices 30a, 30b.
Accordingly, the positional relationship of the vibration control devices 30a, 30b,
the wiping nozzles 12a, 12b, and the outer nozzles 15a, 15b is determined.
[0050] The above described vibration control device 30a includes an electromagnet 31a and
a displacement sensor 32a arranged in this order from below. The vibration control
device 30b includes an electromagnet 31b and a displacement sensor 32b arranged in
this order from below. The number and arrangement of the electromagnets 31a, 31b,
and the displacement sensors 32a, 32b may be modified. For instance, another electromagnet
may be disposed further above the displacement sensors 32a, 32b.
[0051] In each of the vibration control devices 30a, 30b, each of the displacement sensors
32a, 32b (position displacement detection unit) is an eddy-current type sensor, for
instance, for detecting the position displacement of the strip S in the strip thickness
direction. Furthermore, the electromagnets 31a, 31b are configured to change the electromagnetic
force on the basis of the position displacement detected by the displacement sensors
32a, 32b, to maintain the position of the strip S in the strip thickness direction
at a constant position. It is not always necessary to provide both of the displacement
sensors 32a, 32b. If the displacement sensor 32a is not provided, for instance, the
electromagnetic force of the electromagnets 31a, 31b may be changed on the basis of
the position displacement detected by the displacement sensor 32b.
[0052] In this configuration, in each of the vibration control devices 30a, 30b, the displacement
sensors 32a, 32b disposed to face each other constantly detect the position displacement
of the strip S in the strip thickness direction. Furthermore, on the basis of the
detected position displacement, the electromagnetic force of each electromagnet 31a,
31b is controlled so that the strip S is at a constant position between the wiping
nozzles 12a and 12b (normally, center position). Accordingly, a plurality of pairs
of vibration control devices 30a, 30b correct the shape (warp) of the strip S, and
control vibration of the strip S.
[0053] As described above, the positional relationship of the vibration control devices
30a, 30b, the wiping nozzles 12a, 12b, and the outer nozzles 15a, 15b is constant.
Further, even if the strip S warps or vibrates, the vibration control devices 30a,
30b can adjust the position of the strip S with respect to the strip thickness direction
to a constant position between the wiping nozzles 12a and 12b (e.g. center position).
That is, it is possible to maintain the positions of the wiping nozzles 12a, 12b relative
to end portions of the strip S in the strip thickness direction at constant positions.
Similarly, it is possible to maintain the positions of the outer nozzles 15a, 15b
relative to end portions of the strip S in the strip thickness direction at constant
positions.
[0054] Accordingly, it is possible to adjust and maintain an appropriate positional relationship
for the splashes Ms produced at each end portion of the strip S and the two air streams
Fa, Fb from the outer nozzles 15a, 15b, in the strip thickness direction. For instance,
the positional relationship as described in FIG. 4 may be achieved. As a result, it
is possible to appropriately suppress diffusion of the splashes Ms with the air streams
Fa, Fb.
(Working example 4)
[0055] The molten metal plating facility of the present working example is based on the
molten metal plating facility shown in the above working example 2, further including
the configuration shown in the above working example 3. Thus, the same features as
those in the molten metal plating facility of working example 2 and working example
3 shown in FIGs. 5 to 8 are associated with the same reference numerals, and the overlapping
configuration is not described again.
[0056] In the molten metal plating facility according to the present working example, the
above described strip end detection sensor 21 is disposed on the vibration control
device 30a on each of both end portions, as shown in FIG. 9. Furthermore, the above
described driving devices 22a, 22b are configured to be capable of moving the plurality
of pairs of vibration control devices 30a, 30b in the strip width direction. Further,
in this case, the wiping nozzles 12a, 12b are mounted to support members supporting
the vibration control devices 30a, 30b movably. While only one end portion of the
strip S is shown in FIG. 9, the other end portion has the same configuration. Furthermore,
the number and arrangement of the strip end detection sensors 21 may be changed. For
instance, a strip end detection sensor 21 may be disposed on the vibration control
device 30b on each of both end portions, or on each of the vibration control devices
30a and 30b on each of both end portions.
[0057] In this configuration, the strip end detection sensors 21 at both end portions constantly
detect the blade end positions of both end portions of the strip S. The control devices
20 move the vibration control devices 30a, 30b and the outer nozzles 15a, 15b on both
end portions to the positions corresponding to the strip end positions, with respect
to the strip with direction, on the basis of the detected strip end positions of both
end portions of the strip S, by using the driving devices 22a, 22b on both end portions.
Furthermore, the vibration control devices 30a, 30b other than those on both end portions
are also moved so as to adjust the distance between adjacent pairs of vibration control
devices 30a, 30b in response to the strip with of the strip S.
[0058] In this configuration, in each vibration control device 30a, 30b, the displacement
sensors 32a, 32b disposed to face each other constantly detect the position displacement
of the strip S in the strip thickness direction. Furthermore, on the basis of the
detected position displacement, the electromagnetic force of each electromagnet 31a,
31b is controlled so that the strip S is at a constant position between the wiping
nozzles 12a, 12b (normally, center position).
[0059] With the above configuration, similarly to working example 2, even if the strip S
meanders, the strip end positions of both end portions of the strip S are constantly
detected by the strip end detection sensors 21, and thus it is possible to adjust
the vibration control devices 30a, 30b and the outer nozzles 15a, 15b of both end
portions to appropriate positions corresponding to the strip end positions. Further,
similarly to working example 3, even if the strip S warps or vibrates, the vibration
control devices 30a, 30b can adjust the position of the strip S with respect to the
strip thickness direction to a constant position between the wiping nozzles 12a and
12b (e.g. center position). Accordingly, it is possible to adjust and maintain an
appropriate positional relationship for the splashes Ms produced at each end portion
of the strip S and the two air streams Fa, Fb from the outer nozzles 15a, 15b, in
the strip thickness direction and the strip width direction. As a result, it is possible
to appropriately suppress diffusion of the splashes Ms with the air streams Fa, Fb.
Furthermore, it is possible to address strips S having different widths easily.
Industrial Applicability
[0060] The present invention is preferably applicable to a molten metal plating facility
and a molten metal plating method.
Description of Reference Numerals
[0061]
- 11
- Sink roll
- 12a, 12b
- Wiping nozzle
- 15a, 15b
- Outer nozzle
- 20
- Control device
- 21
- Strip end detection sensor
- 22a, 22b
- Driving device
- 30a, 30b
- Vibration control device
- 31a, 31b
- Electromagnet
- 32a, 32b
- Displacement sensor